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Finding the Fourth Proportional to 105.11, 157.46 and 81.21

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Solution

The fourth proportional to 105.11, 157.46 and 81.21 is: 121.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.11 : 157.46 = 81.21 : x
  2. Step 2: Convert to fraction form
    105.11/157.46 = 81.21/x
  3. Step 3: Cross multiply
    105.11x = 157.46 × 81.21
  4. Step 4: Simplify right side
    105.11x = 12,786.92
  5. Step 5: Solve for x
    x = 12,786.92/105.11
  6. Step 6: Final answer
    x = 121.66

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.